Pulp-screening machine



April 14, 1925,

A. J. HAUG PULP SCREENING MACHINE:

Filed March 28. 1921 2 Sheets-Sheet 1 vena?? l dlgy.

April 14, 1925. 1,533,41Q

A. J. HAUG PULP SCREENING MACHINE Filed March 28, 1921 2 Sheets-Sheet 2Patented Apr. 14, 1925.

UNITED STATES ANTON J'. HAUG, 0F NASHA, NEW HAMPSHIRE.

PULP-SCRE'ENING MACHINE. i

Application tiled March 28, 1921;

-To all whom z't may concern Be it known that I, ANToN J. HAUG, acitizen of the United States, residing at Nashua, in the county ofHillsborough and State of New Hampshire, have invented certainImprovements in a Pulp-Screening Machine, of which the followingdescription, in connection with the accompanying drawings, is aspecification, like reference characters on the drawings indicating likeparts in the several figures.

This invention relates to processes of and apparatus for screening pulpand similar materials.

As is Well understood by those familiar with paper making processes, itis necessary to subject the pulp to one or more screening operations inorder to remove the splinters and large pieces of material which havenot been reduced to the desired fibrous condition. Usually several ofthese screening operations are necessary.

The power consumed in these operations, the time required by them, andthe amount of good stock lost in screening are important factors. Animportant object of my invention, therefore, is to improve the processesof and apparatus for screenin pul which will reduce the time consume,will be economical in power, and will save a high percentage of the goodstock.

The screening apparatus provided by this invention has as an importantfeature a submerged rapidly rotating screen. It also includes novelmeans for disposing quickly and positively of the tailings and residualstock.

An importan? advantage of this machine is that the ra io between itsscreening capacity and the screen area and the power consumed are veryfavorable indeed when compared with the results produced by othermachines.

' This invention also includes a novel process which may be carried outby the ma-y chine herein shown or in other Ways.

The invention will be herein disclosed as embodied in a machine desi nedespecially Yfor the screening of pulp o? the character used in themanufacture of aper, although itwill be understood that t e invention isnot limited to use in this particular art.

Referring now to the accompanying drawings,

Figure 1 is a longitudinal-cross sectional utc, f

Serial No. 456,874.

View of a pulp screening ing the invention in the preferred;

Fig. 2 is a vertical transverse cross sectional view on Vthe line 2 2,Fig. 1; and

Fig. 3 is a view partly in cross section on the. line 3-3, Fig. 1, andpartly in end ele- Vation.

The machine shown comprises a rotatable screening drum, indicated ingeneral at 2, having two solid or imperforate end members 3 and 4,respectivel connected by suitable parts which sup-port the screen 5. Thehead or end member 3 of the drum is secured fast to one end of a shaft 6that is mounted in bearings 7 and 8, this `shaft being provided With apulley 9 by means of which the screen may be'driven rapldly, forinstance with a peripheral speed of 1600 ft. er minrom any convenientsource o power. head 4 at the opposite end of the drum has formedintegral therewith or secured fast thereto a hollow shaft 12 which runsin roller bearings 13.

The entire drum is supported in a casing 14 which is ada ted to befilled with pul or other liquid and it has an outlet 15, Figs. 2 and 3,which is provided with an adjustable Weir 16. The bearin brackets yandthe casin are mounted on a ed plate 17.

ounted within the screening drum 2 is a hollow stationary drum 18. Thestock to be screened is delivered to the interior of the screening drum2 by a conduit 19 provided with an inlet channel 20 which dischargesinto a bell mouth portion 21 of the stationmachine embodyform at.present The `ary drum 18. It will be seen from an inspection` of Fig. 1that the drum head or end member 3 is provided with a central projection22 that extends into the bell mouth 21 and has walls parallel to thewalls of they mouth 21.

The pulp to be screened is delivered to the channel 21 from a suitablehead box or other convenient arrangement preferably designed to maintaina relatively low but substantially constant head on the incoming streamof p-ulp. This pulp is discharged against the imperforate head 3 of thescreening drum andis distributed substantially uniformly to all partscircumferentially of the left-hand end,

ig. 1, ofithe screening drum. The pulp then flows backwardly withreference. to the direction of the inflow, that is', toward the right,Fig. 1, along the screening surface. Th:

rapid rotation of the screen 5 imparts a similar movement to the pulpthat is closely adjacent to the screening surface, and the pulp so setin motion is urged through the screen due to the action of centrifugalforce. Consequently, a substantial portion of the pulp passes throughthe screen 5 in the early sta of its backward flow. The continuous feeing of stock to the screen and the centrifugal force imparted by therotating drum, which has a levelling effect on the stock with relationVto the screen surface, :force the stock not immediately screenedtowards the discharge end of the drum.

The foregoing operation of the submerged screen is utilized in forcingthe residual stock or tailings, including the splinters and largeparticles that cannot pass through the screen, along successive portionsof the screening surface. As the stock is constantly fed from the stocktank throu h the stationary drum to the screen 5 and there acquires arotating movement, all the stock not assing through the screen'tends toproceed 1n a helical course towards the discharge end of the machine. Byreason of the perforations in the screen, the good stock begins at onceto flow out. The tailings, however, tend to collect on the screen, and'Ifind it desirable to move them positively to the discharge end of thedrum.' For this purpose a series of blade-like members 24 are formedintegral with or are secured to the outer surface of the stationary drum18. These blades are inclined and preferably have as little clearance asis practical with relation to the interior surface of the screen. lnconsquence, the blades move positively towards the discharge endof themachine, any tailings which have collected on the perforations of thescreen. The rotating liquid stock will also be caused to travel insubstantially a redetermined course or path through the rum. Usuallythese blades are Y inclined so that they advance the tailings in a moreor less helical path toward the end member 4 of the drum. The stock thusis presented to substant ally all portions of the screening surface ofthe drum as uniformly as racticable.

s the tailings near the head 4 of the drum they come into contact with astationary scraper 25 (see Figs. 1 and 3) which guides them into atailings discharge channel 26 formed in the upper part of the conduit19.

Attention is called to the fact that this construction effects theremoval of fthe tailings at an upper point of the machine, thusnvobviating the necessity of pumps to raise the tailings tothe level,ofthe inlet of a subsequent mach'ne into which they .may be fed.

For the purpose of washing the tailings durngtheir rogress through thescreening drum 2 and t us removing all the good pulp ncaa-no from them,I preferto provide a water chamber 28 in the end of the stationar drum1S op site the mouth of the inlet c annel 20, an water is delivered tothis chamber through a channel 29, Figs. 1 and 3, formed in the conduit19. ings 30 is formed in the outer wall of this chamber so that water isdirected through them and mixed with the tailings while they are beinadvanced along the screening surface 5. his supplemental supply of waterfor washing the tailings is not always required.

A spray of clean water or other fluid may also be directed against thescreen 5 from a pipe 32 which is set into a recess or groove formed inone of the plates of the casing 14. This spra is utilized to clean thescreening surface o the drum, and it preferably has sufficient power tooperate satisfactorily, even when the top of the screen drum is entirelysubmerged; but if any difficulty is experienced in clearing theperforations of the drum, the level of the stock outside of` the screenmay be lowered so screen drum will be exposed to the spray.

It will now be understood that the stock to be screened is led into thescreening cylin- `der through the inlet 20 and is distributedcircumferentially over the screening surface of the drum, the screenedpulp passing thro h the screen 5, filling thercasing 14 and owing out ofthe outlet passage 15. The Weir 16 preferably is adjusted at such aheight that the drum 2, or all except the top portion thereof, isconstantly maintained su merged in screened pulp, since I nd that thispractice facilitates the screening operation particularly in that itreduces the tendency of the pulp to mat on or adhere to the screen 5.The tailings work along the inner surface of the drum and are ejectedfrom the machine in the manner above described. Stuffing boxes 33 and 34are provided, rcspectively, where the shafts 6 and 12 pass through t ecasing 14 to prevent thc leakage of liquid from the casing at thesepoints.

It should be noted that since the tailings are moved forward at a ratedetermined by the head andsup ly of the stock, the speed of revolutionof t e screen drum and by the number, inclination and arrangement of theblades 24, by properly predetermining these factors the tailings wi lremain within the screen drum long enough, to ensure their thoroughwashing and a practically complete separation of the good stock fromthem. At the same time their discharge "from the machine is effectedwith sufficient rapidity to prevent their blocking thc scFeen and prevening the through the erforations.

Attention is also called -to the fact that in this machine' the stock,constantly mainthat the top of the A series of discharge openllll) huldischarge of good stock Areservoir my machine will still i,iiss,41o

tained in a proper condition for screening, is distributed evenly oversubstantially the entire area of the screening surface, which is at alltimes ready to receive it, and is screened there by centrifugal forceurging it through the meshes of the drum. The drum rotates atapproximately the same speed as the stock so that there is littlerelative movement of the meshes and stock and the long libres thusproceed out throuvh the meshes into the pond 33 and are not lbentviolently across the meshes of the screen Where they would form, withother fibres, a filter inipervious to stock, as happens when the stockis caused to revolve rapidly in a stationary drum. Since it is necessarymerely to rotate the screening drum, this machine requires only a'relatively small part of the power required in most machines to drivethe usual impellers that throw the inflowing stock outwardly against thescreen. Furthermore, since the drum may be completely submerged itsentire screening surface may be utilized constantly in performing thescreening operation, and the maximum capacity for a given screening areatherefore is obtained.

It is not necessary for good results to have the top of the Weir as highas the tpI of the screen drum, and the minimum height Imay be determinedreadily by the machine tender. If the drum is not run in a pond or havecertain advantages but will lose a great part of its effectiveness as apulp screen.

It Will be understood that While I have herein shown and described thebest embodiment of the invention of which I am at present aware, thisembodiment may be modified in many particulars without departing fromthe splrit or scope of this invention. For instance, the stock to bescreened can be supplied in other ways than that specifically shown andvarious other modifications may be made in the apparatus while retainingthe general principles on which the invention proceeds. be,appreciatedthat the method herein disclosed may be practiced by other forms ofapparatus thanV that shown and described.

hat is claimed as new is:

1. A pulp screening machinecomprising,

in combination, a rotary screening drum, means for rotating the samerap-idly, whereby a substantial centrifugal effect is produced on thestock contained therein, means for delivering Stock to he screened tothe interior of said drinn, and a casing in which said drum is mountedconstructed to receive the screened pulp and maintain a head of the sameabout the screening drum.

2. yA pulp screening machine comprising, in combination, a rotaryscreening drum, means for rotating the same rapidly, whereby asubstantial centrifugal effect is -produced on the stock containedtherein. means It will also for deliverino' stock to be screened to theinterior of said drum, a casing in which llic drum is mounted and intowhich the screened stock is discharged,` said casing holding a supply ofscreened stock in which said drum rotates, and means for coni'luctingtlic tailings from the interior of said drinn to a point outside of saidcasing.

3. A pulp screening mac line comprising, in combination, a rotaryscreening drum, means for rotating the same rapidly, whereby asubstantial centrifugal effect is produced on the stock containedtherein, means for delivering stock to be screened to the interior ofsaid drum, and stationary means cooperating with said driiiirto more thetailings in a substantially lircdclcriiined course through the drum.

4. A pulp screeniugniacliine comprising, in combination, a rotaryscreening driini, means for rotating the saine rapidly, whereby asubstantial centrifugal elfectis produced on the stock containedtherein, means for delivering stock to be screened iothe interior ofsaid driim,'and stationary inraiis for moving the tailings through thedriini at a rate depending upon the speed of rotation of the drum.

5. A pulp screening machine haring, in combination, a horizontalrotatable screening drum, means for rotating said drinn rapidly, wherebya substantial centrifugal effect is produced on the stock containedtherein, a casing in which said drinn is mounted arranged to receive thescreened product and maintain a head of the saine about the screeningdrum at a predetermined height, an inlet for feeding the imiterial to bescreened' into the screening drinn to the screening surface, a dischargeoutlet for stock rejected by the screen, and means for forcing therejected stock from the screening surface to said discharge outlet.

6. A pulp screening machine having. in combination, a horizontalrotatable screening drun'i, means for rotating said di'iiiii rapidly, acasing in which said drinn is mounted arranged to receive the screenedproduct and maintain a head of the same about the screening drum at apredetermined height, means for feeding the material to be screened intothe screening drum. means for conducting tailings out of said drum, andstationary blades for forcing the tailings from the screening surface tothe discharge therefor.

'i'. A pulp screening machine comprising, in combination, a rotaryscreening drinn, means for rotating said drum rapidly, whereby asubstantial centrifugal effect is produced on the stock containedtherein, means for delivering stock to he screened to the interior ofsaid drum. relatively stationary means nioiinted within the drinn formoving the tailings through the drum, and means for mixing water withsaid tailings during their travel through the drum.

8. A pulp screening machine comprising, in combination, a rotarscreening drum, means for rotating said drum rapidly, means fordelivering stock t0 be screened to the interior of said drum, bladesmounted within said drum to advance the tailings toward one end of thedrum, and a stationary scraper mounted within said drum for ejecting thetailings from the drum.

9. A pulp screenin machine comprising, in -ombination, a horizontalscreening drum, a ,asing in which said drum is mounted, means vforrotating said drum rapidly, whereby a substantial centrifugal eil'ect isproduced on the stock contained therein, means for conducting pulp to bescreened to the interior of said drum, and means within the drum fordistributing the pulp substantially uniformly over the entire screeningsurface of the drum.

10. A pulp screening machine comprising, in combination, a casing, arotary screening drum mounted within said casing, means for` rotatingsaid drum rapidly, whereby a substantial centrifugal effect is producedon the stock contained therein, means for delivering stock to bescreened to said drum, and means for presenting unscreened portions ofthe stock within the drum to successive parts of the screening surfaceof the drum.

11. A pulp screening machine comprising, in combination, a rotaryscreening drum, means -for delivering stock to be screened to theinterior of said drum, and means for dischargzgini;r the tailings fromsaid drum at a point above the axis of rotation of the drum.

12. A pulp screening machine comprising, in combination. a rotaryscreening drum, lmeans for rotating said drum rapidly whereby asubstantial centrifugal effect is produced on the stock containedtherein, and conducting means for leading stock into said drinn at oneend thereof and for dischar ing tailings from the drum at the same en13. A pulp screening machine comprising, in comblnation, a rotaryscreening drum, means for rotating said drum rapidly whereby asubstantial centrifugal effect is produced on the stock containedtherein, conducting means for leading stock into said drum at one endthereof, and means connected with the opposite end of said drum fordriving it.

14. A pulp screening machine comprising, in combination, a rotaryscreening drum, means for rotating said by a substantial centrifu aleffect is produced on the stock contained therein, means for deliveringstockto be screened to the interior of said drum including a conduitdischarp drum rapidly where-Y ing into said drum at one end thereof, andmeans within said drum for working the tailings toward the opposite endof the drum.

15. A pulp screening machine comprising, in combination, a horizontalscreening drum, a head closing one end of said drum, a rotary shaftsecured to said head for driving the drum, a hollow shaft supporting theopposite end of said drum., bearings in which said shafts are mounted,and means for conductingmaterial to be screened through said hollowshaft into the interior of said drum.

1G. In a pulp screening machine, the combination of a horizontalscreening drum, a hollow shaft supporting one end of said drum, abearing supporting said shaft for rotation, supply and dischargeconduits leading through said hollow shaft to and from sai'd drum, andmeans for supporting the opposite end of said drum.

17. A pulp screening machine comprising, in combination, a horizontalscreening drum means for supporting and rotating said drum, a stationarysupport mounted within said screening drum, and means mounted on saidsupport for distributing the stock along .the screening surface of saiddrum.

18. A pulp screening machine comprising, in combination, a horizontalscreening drum having heads at its op osite ends, shafts secured to saidheads or sup orting them, bearings supportin said sha means carried byone of sai shafts whereby it may be driven to rotate said drum, andmeans for discharging the stock to be screened a ainst the inner surfaceof the head to whic the last mentioned shaft is secured.

19. A pulp screening machine comprising, in combinatlon, a. horizontalscreening drum having heads at its opposite ends, means for supportingand rotating said drum, a stationary drum mounted within said ,screeningdrum, means for conducting the stock to bc screened through saidstationary drum and directing it against one of said heads, stockdistributing members supported b'y said stationary drum, and meansadjacent to the other of said heads for discharging the tailings fromthe drum.

20.' In a ul screening machine, the com, bination o a orizontalscreening drum, a hollow shaft Vsupporting one end of said drum, abearing supporting said shaft, a conduit extending through said hollowshaft and having a stock inlet channel leading into said drum and' atailings discharge channel leading from said drum.

21. A pul screening machine of the character descri comprising, incombination, a horizontal screening drum, means for supporting androtating said drum, a stationary drum mounted within said screeningdrum, means for conductin stock to be screened into said screening rum,a water`chamber in said stationary drum having discharge outlets openingfrom the periphery thereof, and means for advancing the tailings alongthe surface of said screening drum and into position to be mixed withthe Awater discharged from said chamber.

22. That improvement in the process of scieeiiing pulp, which consistsin performing the screening operation by centrifugal force against thehead of surrounding screened liquid, and creating said force throughmotion of the screen itself.

' 23. That improvement in the process of screening pulp, which consistsin urging the pulp through the screen by centrifugal force, creatingsaid force throii h the motion of the screen itself, and utilizing saidmotion to remove the` tailings positively from thcscreening surface.

24. That improvement in the process of screening pulp, which consists inurging the pulp through the screen by centrifugal force, creating saidforce through the motion of the screen itself, and maintaining onesurface of the screen substantially submerged in screened pulp and theother surface in unscreened pulp.

25. That improvement in the process of screening pulp, which consists inowing the pul into contact with a screen, rotating sai screen rapidly tocreate a -stron centrifugal force urging the pulp throng the screen,maintaining the outer surface of the screen substantially submerged inscreened pulp, and utilizing-said motion of the screen to discharge thetailings from the screening surface.

26. A pulp screening machine comprising, in combination, a rotarycylindrical screeniriig drum, means for rotating the same rapiy, wherebya substantial centrifugal effect is produced on the stock containedtherein, means for delivering stock to be screened to theV interior ofsaid`drnm, and a casin Vmeans for delivering the stock to be screened tothe interior of said di-um, a casing in which the drum is mounted andinto which in` which said drum is mounted constructe toV the screenedstock is discharged, said casing holding ii supply of screened stock inwhich Vsaid drum rotates, and means for conductthe tailings in asubstantially predetermined course through the drum.

29. A pulp screening machine comprising, in combination, a rotarycylindrical screening drinn, means for rotating the same rap'- idIy,whereby a substantial centrifugal effect is produced on thestockcontained therein, means for delivering the stock to be screened to theinterior of said drum, and stationary means for moving the tailingsthrough the drum at a rate depending upon the speed of rotation of thedrinn.

3D. A pulp screening machine comprising, in combination, a rotaryscreening drum.l means for rotating said drum with suicient speed tocause it to exert a substantial centrifugal effect on the stock incontact therewith, 'and means for Vmaintaining said drum completelysubmerged 'in screened stock.

' 31. A pulp screening machine comprising, in combination, a horizontalrotary screening drum, means `for rotating said drum with suicient speedto cause it to exert a substantial centrifugal effect on the stock incontact therewith, a casing in which said drum is enclosed, and a Weirover which the screened vstock discharged from said casing flows, saidwer being arranged to back up the screened stock in said casing and keepsaid drum completely submerged in screened stock. Y

32. That improvement in the process of screening pulp which consists inurging the pul through the screen by centrifugal force, an maintainingsaid screen completely submerged i'ii and under a hydraulic head of thescreened stock.

In testimony whereofV I have signed my name to this'specicaton.

i ANTON J. Haus.

outlets opening from the periphery thereof, und means for advancing thetailings along the surface of said screening drum and into position tobe mixed with the water discharged from said chamber. Y

22. That iinpi'ovement in theprocess of screening pulp, which consistsin performing the screening operation by centrifugal force against thehead of surrounding screened liquid, and creating said force throughmotion of the screen itself.

` 23. That improvement in the process of screening pulp, which consistsin urgiu the pulp through the screen by centrifuga force, creating saidforce through the motion of the screen itself, and utilizing said motionto remove the' tailings positively from the 'screening surface.

24. That improvement in the process of screening pulp, which consists inurgin .the pulp through the screen by centrifuga force, creating saidforce through the motion of the screen itself, and maintaining onesurface of the screen substantiallysubmerged in screened pulp and theother surface in unscreened pulp.

25. That improvement 'in the process of screening pulp, which consistsin liowing the pnl into contact with a screen, rotating sai screenrapidly to create a .stron centrifugal force urging the pulp throng thescreen, maintaining the outer surface of the screen substantiallysubmerged in screened pulp, and utilizing-said motion of the screen todischarge the tailings from the screening surface. e 26. A pulpscreening machine comprising, in combination, a rotary cylindricalscreenin drum, means for rotating the same rapidy, Wliereby asubstantial centrifugal effect is produced on the stock -containedtherein, means for delivering stock to be screened to the interior ofsaid `drum, and a casin which said drum is mounted constructs receivethe screened pul and maintain a head of the saine about t ie screeningdrum. 27. A pul screening machine comprising, in combination, a rotarycylindrical screening drum, meansfor rotating the same rapidly, wherebya substantial centrifugal effecty is'produced on the stock containedtherein means for delivering the stock to be screene to the interior ofsaid drum, a casin 111 which the drum is mounted and into w ich in 'A tothe screened stock is discharged, said casing holding a supply ofscreened stock in which -said drum rotates, and means for conductthetailings in a substantially predetermined course through the drum.

29. A pulp screening machine comprising, in combination, a rotarycylindrical screen ing drum, means for rotating the same rapidly,whereby a substantial centrifugal eii'ec is produced on thestoclrcontained therein, means for delivering the stock to be screened to theinterior of said drum, and stationary means for moving the tailingsthrough the drum at a rate depending upon the speed of rotation of thedrum.

30. A pulp screening machine comprising, in combination, a rotaryscreening drum., means for rotating .said drum with sufficient speed tocause it to exert a substantial eentrifugal eii'ect on the stock incontact therewith, and means for maintaining said drum completelysubmerged in screened stock.

' 31. A. pulp screening machine comprising, in combination, a horizontalrotary screening drum, means for rotating sai-d drum with suicieut speedto cause it to exert a substantial centrifugal eifect on the stock incontact therewith, a casing in which said drum is enclosed, and a Weirover which the screened stock discharged from said casing ows, said Weirbeing arranged to back up the screened stock inl said casing and keesaid drum completely submerged in scrcene stock.

32. That improvement in the process of screening pulp which consists inurging the pulp through the screen by centrifugal force, and maintainingsaid screen com lctely submerged i'n and under a hydraulic ead of thescreened stock.

In testimony whereof I have signed Amy name to thisspecification.

ANTON J. HAUG.

DISCLAIMER Hereby zontal axis 'amai 4mm', 1o, 193s.)

410.-Auton J. Haug, ashua,.N. H. PULP-SCREENING MACHINE. -Patentdated-April 14, 1925. Disclaimer led December 14, 1932, by the patentee.

disclaims from the scope of said claim 32, -anydproeesslof screening yrevoY ul fue? ved about a DISCLAIMER 1,533,410.-Amon J. Haug, Nashua, N.H. PULP-SCREENING MACHINE. Patent dated April 14, 1925. Disclaimer ledDecember 14, 1932, by the patentes. Hereby disclaims from the scope ofsaid claim 32, any process of screening gulp excelJ processes in whichan enclosed body of pulp is rapid y revolved about a orizonb axis.

Gazette January 10, 1.933.)

